Transoral laser microsurgery for T1 glottic cancer with anterior commissure: Identifying clinical and radiological variables that predict oncological outcome

Abstract

Purpose: The involvement of the anterior commissure (AC) is regarded to be a risk factor for poor results after transoral laser microsurgery (TLM) for early glottic cancer. The objective of this study was to determine how AC-related clinical and radiological factors affected oncological outcomes in a cohort of patients with T1 stage early glottic carcinoma involving the anterior commissure who were treated with TLM with negative surgical margins.

Methods: Retrospective analysis was performed on clinical, radiological, and follow-up data of patients consecutively treated with TLM at a tertiary academic center between November 2011 and August 2021 for T1 glottic squamous cell carcinoma involving the anterior commissure. Recurrence-free survival (RFS), local control with laser alone (LCL), laryngeal preservation (LP), and overall survival (OS) rates (Kaplan-Meier) were the primary outcome metrics.

Results: In our series, 5-year OS probability was 75.1%, RFS was 64.8%, LCL was 73.8%, and LP was 83.4%. OS and RFS were higher in patients with early stages of AC pattern than in patients with advanced stage (p = 0.004, p = 0.034, respectively). Vertical extension ratio was found to be associated with OS and RFS (p = 0.023, p = 0.001, respectively), and thyroid cartilage interlaminar angle with LCL by multiple Cox regression analysis (p = 0.041).

Conclusion: TLM remains a valuable treatment option for AC involvement. AC3 type involvement and elevated vertical extension ratio were associated with negative prognosis. There have been signs that thyroid cartilage with a narrow angle increases recurrence. Alternative modalities should be kept in mind in the treatment decision of these cases.

Keywords: Anterior commissure; Early stage glottic cancer; Thyroid cartilage angle; Transoral laser microsurgery.

Fig. 1

The computed tomography sections supplied depict representative instances of measurements for three parameters associated with the anterior commissure, which are utilized in the radiological assessment of patients involved in the study. These are listed as follows; a Measurement of the thickness of the anterior commissure in the section passing through the anterior commissure in the axial plane, b Measurement of the angle between the two laminae of the thyroid cartilage in the section passing through the anterior commissure in the axial plane, c Measurement of the vertical length of the tumor in the section passing through the anterior commissure in the sagittal plane, d Measurement in the coronal plane of glottic distance (vertical extension ratio was obtained by dividing the measurement in Fig. 1c to the measurement in Fig. 1d)

Fig. 2

Kaplan–Meier curves for the study population. a Overall survival curve b Disease-specific survival curve c Recurrence-free survival curve d Local control with laser alone survival curve e Laryngeal preservation survival curve. Abbreviation: Cum Survival, Cumulative Survival

Fig. 3

a Analysis of the overall survival of T1 tumors with respect to anterior commissure involvement pattern. *p = 0.004 compared with AC1 and AC2 by AC3. b Analysis of the recurrence-free survival of T1 tumors with respect to anterior commissure involvement pattern. *p = 0.034 compared with AC1 and AC2 by AC3. c Analysis of the local control with laser alone survival of T1 tumors with respect to anterior commissure involvement pattern. AC anterior commissure

Fig. 4

Display of thyroid cartilage interlaminar angle values respect to recurrence status in the violin plot